The present inventive process and product produced thereby has evolved as an answer to problems which have been encountered in providing a manifold for interconnecting the struts of a strutted film wherein the struts are of irregular widths and spacings. The present invention also overcomes the problems confronting those skilled in the art when attempting to interconnect struts in a fluid tight manner which, as a result of their method of manufacture, are not readily interconnectable by heat sealing.
The terminology "strutted films" is used herein to generally refer to films which have been provided with internal passageways through which liquids or other materials may readily flow. One major area of application for such films is the solar energy area where the films may be utilized as solar collectors through appropriate placement and location. Another possible utilization for strutted films is in irrigation. In this utilization the strutted passageways are provided with spaced-apart orifices whereby the liquid passing therethrough may exit the passageways at appropriate locations and rates.
One method of manufacturing a strutted film is by coextrusion whereby an incompatible and thus non-adhering material is extruded internally and thus trapped between the extruded layers. After extrusion, the internally trapped, incompatible, non-adhering material may be physically separated from the adjoining surrounding layers and thereby provide an internal passageway or strut through the extruded film. Since the internally extruded material is, by its very nature, incompatible with at least one interior surface of one adjoining layer, problems have arisen in attempting to seal off the strutted film by heat sealing. In fact, closing of the struts by heat sealing has been found to be extremely difficult if not impossible.